兴安盟暴雪时空变化特征及重现期分析

Analysis of the Spatiotemporal Variation Characteristics and Return Periods of Blizzard in Hinggan League

暴雪是兴安盟最主要的灾害性天气之一,对区域性暴雪的统计分析能够为生产生活、城镇建设、交通运输等人类活动提供高信度且有针对性的参考信息。文章根据1981—2022年兴安盟8个国家气象站的降雪量、积雪深度、天气现象等历史气象要素,基于耿贝尔极值分布推算出不同重现期下的极端降雪量。结果表明:(1)兴安盟暴雪日数存在从逐渐减少到基本持平的年代际变化特征,年降雪量极值和站点比例在相应时间段表现出较为一致的变化趋势,21世纪10年代以来极端降雪事件发生频繁,极端性特征显著。多站点在2020年前后存在较为显著的降雪极值震荡,均在这一时期达到或接近降雪极值。(2)最大日降雪量较高的区域集中在兴安盟海拔高度较高的北部和西北部地区。最大日降雪量和暴雪总日数的空间分布特征极为相似,均表现出北多南少、北高南低的特征。(3)兴安盟南部各气象站点在不同重现期下的降雪极值相对较小;北部以及西北部降雪强度较高,风险相对较高,需关注极端灾害性天气的可能影响及风险。

Blizzard is one of the major disastrous weather in Hinggan League.Statistical analysis of regional blizzard can provide reference information for human activities such as production and living of society,urban construction,transportation and so on.Based on the precipitation,snow depth and weather phenomena data of 8 national meteorological observing stations in Hinggan League from 1981 to 2022,the extreme snowfalls in different return periods were calculated according to Gumbel distribution.The results were as follows:(1)The number of heavy snowfall days in Hinggan League changed from gradually decreasing to basically stable on the interdecadal scale,and the extreme annual snowfall and the proportion of stations showed a relatively consistent trend.Extreme snowfall events had occurred frequently since the 2010s,and the extreme characteristics were significant.In many observing stations,there was a relatively significant snowfall extreme oscillation around 2020,and the snowfalls reached or approached the snowfall extremes during this period.(2)The areas with higher daily snowfall were concentrated in the northern and northwestern areas with higher altitude of Hinggan League.The spatial distribution characteristics of the maximum daily snowfall and the total number of snowstorm days were similar,which were more in the north and less in the south.(3)The extreme snowfalls of the stations in the north and northwest of Hinggan League under different return periods were larger than those in south areas,attention should be paid to the possible impact and risk of extreme disastrous weather.